A server has been intermittently shutting off. The power going to the server was tested and is giving the appropriate voltages. Which of the following tools would be used to test the power supply?

A POST diagnostic card helps troubleshoot boot sequence failures by displaying error codes, but it does not directly test power supply output voltages.

An OTDR (Optical Time-Domain Reflectometer) is specifically designed for testing and troubleshooting fiber optic cables, not server power supplies.

A TDR (Time-Domain Reflectometer) is used for testing copper cables to locate faults or measure length, making it irrelevant for power supply testing.

A multimeter is an essential tool for measuring electrical properties such as voltage, current, and resistance. It can accurately test the output rails of a server's power supply unit (PSU) to confirm if it is delivering stable and correct voltages (+12V, +5V, +3.3V) to the internal components, which is critical for identifying a failing or intermittent PSU.